Dinophysis Toxigenicity

Okadaic acid and DinophysisDinoflagellates, Dinophysis acuminata and D. ovum, were cultured using a three stage feeding system: cryptophytes were fed to ciliates, which were fed to the mixotroph Dinophysis. Culturing experiments were conducted to determine environmental drivers of growth and toxin production (okadaic acid, dinophysistoxins, pectenotoxins).
Photo by J. Smith

Abstract: The dinoflagellate genus Dinophysis is important from ecological, evolutionary, and public health perspectives. In the former category, some members of this genus derive their nutrition through a unique, multi-stage process requiring both cryptophyte and ciliate prey. Evolutionarily, the modification of cryptophyte chloroplasts during this complex feeding process and their subsequent utilization for photosynthesis provides an ideal model system for investigations of plastid acquisition and evolution in eukaryotes. From the public health perspective, Dinophysis species are responsible for the vast majority of diarrhetic shellfish poisoning (DSP) cases. DSP is a syndrome associated with human consumption of shellfish that have accumulated Dinophysis toxins (Yasumoto et al., 1980), and less frequently, toxins from Prorocentrum lima (Lawrence et al., 1998). It is a major public health and economic problem for many countries (Boni et al., 1993; Giacobbe et al., 2000) and is among the most important and widespread of the harmful algal bloom (HAB)-associated poisoning syndromes (Van Dolah, 2000).

For decades, many aspects of Dinophysis physiology, toxicity, and genetics have remained intractable due to our inability to grow these organisms in laboratory cultures. As a result of a recent breakthrough, however, this obstacle no longer exists and an array of important experiments and measurements are now possible. The opportunities for major advances on multiple fronts are significant. Here we propose a comprehensive study to investigate nutritional, environmental, and genetic regulation of toxicity and growth in Dinophysis.